This project investigates environmental factors that contribute to the development of cognitive and social competencies during the first two years of life. Before children are old enough to enter formal social learning situations, nearly all of their experiences stem directly from interactions they have with their primary caretakers. Four conceptually distinct categories of caretaker-child interactions can be identified: nurturant, material, social, and didactic. These encompass much of the everyday behavior of infants' caretakers. In previous work using samples of convenience, the Principal Investigator linked the latter two types of caretaking to cognitive development in babies. In the present study set, this work is being replicated and extended by focusing on the extent to which three maternal characteristics (age, employment status, and parenthood status) and type of substitute care experienced during mother's employment influence the observed relations between caregiver social and didactic stimulation on the one hand and infant social and cognitive competencies on the other. In addition, in a short-term longitudinal extension of the study, measures of toddler functioning (i.e., play competence, language development, and social adaptation) and maternal behavior (i.e., encouragement of attention to the environment and I.Q.) are being obtained, thereby permitting examination of associations between aspects of mother-infant interaction in early infancy and the development of important aspects of cognitive and social competencies in the second year.